Description

Adding documentation for error handling

Motivation and Context

There is a designed flow for how to do the error handling in the User Office. This document tries to summarize it in a short article under the documentation

Changes

1. Addition of a new file error_handling.md under the developer guide. This document provides guidelines on how to handle both expected and unexpected failures in the backend, how to log errors, and how to manage errors outside GraphQL.

2. Update to the mkdocs.yml file to include the newly added Error Handling guide in the navigation structure of our documentation.